The present invention relates to a photocatalyst having excellent visible-light activity because the photocatalyst includes a support on which titanium dioxide doped with a transition metal is supported.
Aromatic organic compounds such as benzene, xylene, toluene, and the like are highly volatile organic compounds that have been industrially widely used as solvents, detergents, and the like, and also used as organic agricultural chemicals such as pesticides, disinfectants, herbicides, and the like in the field of agriculture. However, these organic compounds include components that are toxic and carcinogenic to humans and cause growth disorders, deformities, and the like in animals and plants. As a result, the preparation, use and disposal of the organic compounds have been strictly regulated, but conventional technologies for disposing of aromatic organic compounds have drawbacks in that they require high costs, and it is actually difficult to dispose of the organic compounds due to their low efficiency.
Meanwhile, when a photocatalyst receives light having an energy greater than or equal to band gap energy, the photocatalyst excites electrons from a valence band to a conduction band so that electrons are formed in the conduction band and holes are formed in the valence band. In this case, the formed electrons and holes spread on a surface of the photocatalyst to participate in an oxidation/reduction reaction.
Photocatalysis may be used to directly photodecompose water using solar energy to produce hydrogen as a next-generation alternative source of energy, and may also be used to decompose volatile organic compounds (VOCs), various odors, waste water, non-degradable contaminants and environmental hormones, kill germs and bacteria, and the like. Therefore, photocatalyst technology in which only solar energy is used at room temperature has been applied to produce hydrogen and clean up the environment, and thus has attracted attention as a powerful means capable of solving environmental issues.
However, in the case of titanium dioxide (TiO2) which has been widely used as the photocatalyst, photocatalysis occurs only in an ultraviolet region including approximately 4% of total sunlight, as disclosed in US Patent Application Publication No. 2012-0171079. Also, photocatalysis has a problem in that ultraviolet (UV) light causes diseases such as skin cancer when organisms are exposed to the UV light.
Therefore, to effectively utilize the photocatalyst technology to remove the organic compounds, there is an urgent demand for the development of photocatalyst materials that have a high activity in a visible light region which accounts for approximately 43% of total sunlight.